Field Observations on Varanus macraei

RAUL DEL CANTOE-mail: herprif@hotmail.com

Biawak, 7(1), pp. 18-20© 2013 by International Varanid Interest Group

Abstract – Field observations on the occurrence and natural history of Varanus macraei near Mandui village, Batanta are reported. Over-collection for the live reptile trade is reported to have nearly extirpated a population of V. macraei on a small island off the coast of Mandui.

Introduction

Although frequently collected for the live reptile trade, very little is known about the natural history of the blue tree monitor Varanus macraei. Described from the island of Batanta in Papua, Indonesia (Böhme & Jacobs, 2001), details on its occurrence in the wild are lacking. Here, I describe field observations on V. macraei made during a brief trip to Batanta in June 2007. Study Site

Mandui, a small village located on the north shore of Batanta (Fig. 1) was reached by boat from Sorong on 13 June 2007 and used as a base camp for the next four days. With the exception of illegal logging vehicles, motor vehicles were absent from Mandui. A local villager who was once a collector for the live reptile trade was hired as a guide. Three days were spent searching for V. macraei in forests outside of Mandui, and one day was spent searching on a small island (ca. 2 km in length) located just off the coast of Mandui (Fig. 2), on which, according to local animal collectors, V. macraei was also reported to occur.

Traveling around Mandui proved to be very difficult. Like many other islands within the Raja Ampat archipelago, Batanta is steeply sloped in many areas (Fig. 3), which, in combination with a wet ground, is easy to lose one’s footing and slide several meters down the slope. Global positioning system (GPS) navigation was ineffective due to the dense forest canopy (Fig. 4). The lowest nighttime temperature recorded at Mandui over the four day period was 22º C. At sunrise (ca. 0600 h), ambient temperatures averaged 24º C, and by 1100

Fig. 1. View of Batanta from Mandui Bay. Fig. 3. View of forested hills on Batanta.

Fig. 2. A small island off the coast of Mandui which al-legedly supported a population of Varanus macraei.

h, temperatures reached 35º C. The highest daytime temperature recorded in the shade at an elevation of 124 m was 37º C. In addition to field searches, approximately 30-40 villagers from Mandui and some small islands visited along the way between Sorong and Batanta were interviewed about the occurrence and natural history of V. macraei.

Observations and Results

In three days of searching in areas around Mandui, only a single V. macraei was observed. It was seen at around 1100 h climbing through the forest canopy in a steeply-sloped section of dense forest (Fig. 5) at an elevation of 124 m above sea level, ca. 4 km east of Mandui. Upon its detection, the monitor fled from tree to tree through the canopy until it finally disappeared from sight. My accompanying guide noted that when alarmed or panicked, V. macraei occasionally jump or fall to the

forest floor, where they are easier to capture. Varanus macraei could not be located on the small island situated off the coast of Mandui. My guide reported that the species had been heavily collected from this island for the pet trade, and that its population there has nearly been extirpated. A female V. macraei with a snout to vent length of 28 cm and a total length of 85 cm was captured by locals one morning (Fig. 6). It was collected in a densely forested area outside of Mandui in late morning using a noose atop a long bamboo cane. Palpation of the animal’s abdomen revealed the presence of eggs and confirmed the collectors’ suspicions that it was a gravid female. Known locally as “Soa soa”, the same name used for other arboreal monitor lizards in the region, V. macraei was reported by villagers in Mandui to become active around 0900 to 1000 h, and retire by 1300 h when temperatures reach their daytime highs. This was corroborated by my guide, who claimed that

Fig. 6. Gravid female V. mac-raei collected by local villag-ers near Mandui, Batanta.

Fig. 4. Dense tropical forest near Mandui.Fig. 5. Forested area where V. macraei was observed by the author.

DEL CANTO - FIELD OBSERVATIONS ON VARANUS MACRAEI19

V. macraei was difficult to find in the afternoon. He also noted that V. macraei is rarely found at elevations below 50 m along the coast, and that it feeds primarily upon grasshoppers (Orthoptera), which were frequently observed and abundant in forestes around Mandui. Varanus macraei is not eaten by villagers in Mandui. Two V. jobiensis were also observed during searches in forested areas; one was seen at sea level and the other at an elevation of 50 m (Fig. 7).

References

Böhme, W. & H.J. Jacobs. 2001. Varanus macraei sp.n., eine neue Waranart der V. prasinus Gruppe aus West Irian, Indonesien. Herpetofauna 23: 5-10.

Fig. 7. Forested site where V. jobiensis was observed.

Received 17 September 2007; Accepted 15 May 2013

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